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A constant-torque two-speed motor is connected to the AC lines

Resolved Question:

A constant-torque two-speed motor is connected to the AC lines to run at high speed. This means that the motor is connected in a






A. single wye.



B. parallel wye.



C. delta.



D. parallel delta.


















2. A motor device is labeled 150 mFd. This device is a






A. rotor.



B. stator.



C. centrifugal switch.



D. capacitor.


















3. A split-phase motor on a cycling pump won't start running. The centrifugal switch appears to be in good condition. What's the next most likely cause of this problem?






A. Open run winding



B. Shorted run winding



C. Open start winding



D. Faulty bearing


















4. At about what percentage of the motor's maximum speed do the centrifugal switch contacts open?






A. 20 %



B. 50 %



C. 70 %



D. 90 %


















5. When a motor's internal coils are connected in a triangle-shaped pattern, this connection is termed a






A. delta connection.



B. wye connection.



C. phase/ground connection.



D. split-phase connection.


















6. A reversing motor starter will have how many large three-phase line-connected contacts?






A. 3



B. 6



C. 8



D. 9


















7. Which of the following type of motor isn't normally reversible?






A. Split phase



B. Capacitor start



C. Repulsion-induction



D. Shaded pole


















8. A name that's often given to an AC induction motor's rotor is the _______ rotor.






A. squirrel-cage



B. dynamically-balanced



C. self-contained



D. repulsion-form


















9. The type of capacitor motor that keeps the capacitor in the motor's circuit is the






A. dual-voltage capacitor motor.



B. series centrifugal-switch motor.



C. permanent split-capacitor motor.



D. constant capacitor motor.


















10. An AFBMA number appears on the nameplate of a motor. This number will identify the motor's






A. duty.



B. bearing size.



C. insulation type.



D. speed rating.


















11. The end rings of a motor will often have small tabs that are used to






A. extend the magnetic field of the rotor.



B. move cooling air over the rotor.



C. decrease internal eddy currents.



D. electrically balance the rotor.


















12. One type of failure that's more common with 200 HP motors than with 10 HP motors is






A. rotor bar failure.



B. stator failures.



C. bearing failure.



D. contactor failure.


















13. At what speed will a four-pole three-phase motor operate at when supplied with 60 Hz?






A. 670 RPM



B. 900 RPM



C. 1800 RPM



D. 3600 RPM


















14. A three-phase motor has a nameplate that reads DUTY PLUGGING. This means that the motor






A. can expect to survive quick loading surges as it runs.



B. is rated for jog or inching duty.



C. has no provision for direct line connection.



D. is a low-current reversible motor with shaded poles.


















15. An AC motor's nameplate has a number 0.92 with the label P.F. This number is XXXXX motor's _______ factor.






A. power



B. performance



C. plugging



D. placement


















16. Rotor slots are often skewed to help reduce






A. starting torque.



B. starting current.



C. magnetic hum.



D. rotor heat.


















17. Rotor eccentricity can be caused by






A. excessive voltage.



B. loose stator coils.



C. high motor loads.



D. poor motor mounting.


















18. The maximum size of a shaded-pole motor is about






A. 1/100 th HP.



B. 1/25 th HP.



C. 1/20 th HP.



D. 1/10 th HP.


















19. A motor starter contains protection devices to prevent an overcurrent condition in the motor's circuit. These devices are known as






A. fuses.



B. circuit breakers.



C. thermal links.



D. thermal overloads.


















20. If a centrifugal switch assembly in a split-phase or capacitor motor fails, you'll most likely have a






A. loudly humming motor.



B. slowly turning motor.



C. motor turning at too high a speed.



D. motor that has reversed direction while running.


















21. A split-phase motor starts properly and runs but quickly overheats. What's the most likely cause of this problem?






A. Open start windings



B. Open run windings



C. Stuck centrifugal switch



D. Bearing problems


















22. Which one of the following types of AC motors uses brushes and a commutator?






A. Shaded-pole



B. Repulsion-induction



C. Split-phase



D. Capacitor start


















23. The deviation in a motor's speed between the nameplate value and the actual value is called






A. stagger.



B. slip.



C. lag.



D. decline.
Submitted: 2 years ago.
Category: Homework
Expert:  Angela--Mod replied 2 years ago.

Hi, I’m a Moderator for this topic and I wonder whether you’re still waiting for an answer. If you are, please let me know and I will do my best to find a Professional to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!

Customer: replied 2 years ago.
Yes I am waiting
Expert:  Angela--Mod replied 1 year ago.

Sometimes, finding the right Professional can take a little longer than expected and we thank you greatly for your understanding. We’ll be in touch again shortly.

Expert:  akch2002 replied 1 year ago.
I can try these questions also.
Customer: replied 1 year ago.
Thank you that'd be great
Expert:  akch2002 replied 1 year ago.
Welcome.
Expert:  akch2002 replied 1 year ago.
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akch2002, Engineer
Category: Homework
Satisfied Customers: 2800
Experience: Home work expert
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